Ultrasonic medical transducers are used to observe the internal organs of a patient. Such an apparatus produces the display of successive images at a rapid rate so that an observer can see movements of an organ in "real time". Curved transducer arrays are used, rather than flat arrays, to enhance the performance of the ultrasonic imaging device. Principally, a curved array will produce an image over a wider field of view and thus permit the observer to view objects that would ordinarily be hidden from view when using a flat array (for example, a bone, such as a rib may obstruct the view of an internal organ).
Typically, curved transducer arrays are fabricated by soldering a flexible circuit board to a flat transducer plate, the transducer plate generally comprising a ceramic substrate sandwiched between conductive electronic plates. A backing material is then bonded to what will become the concave surface of the array. The transducer plate is then cut into segments and subsequently formed into a curvilinear array. The backing material acts as a hinge to allow the segmented ceramic to bend while maintaining positioning between segments.
For example, U.S. Pat. No. 4,734,963 to Ishiyama discloses a method of manufacturing a curvilinear array of ultrasonic transducers wherein a flexible printed circuit board is connected to one edge of a rigid transducer plate. The transducer plate, being previously bonded to a flexible support plate, is then diced through to the support plate thus dividing the transducer plate into a series of parallel transducer elements. The support plate is then conformed to a curved shape.